<template>
  <div class="person">
    <h1>情况一：监视【ref】定义的【基本类型】数据</h1>
    <h2>当前求和为：{{ sum }}</h2>
    <button @click="changeSum">点我sum加一</button>
  </div>
</template>

<script lang="ts" setup name="Person">
  import { ref,watch } from 'vue';
  //数据
  let sum = ref(0);
  //方法
  function changeSum() {
    sum.value++;
  }
  //监视时不用value
  watch(sum,(newValue,oldValue)=>{
    console.log('sum变化了');
    console.log('newValue',newValue);
    console.log('oldValue',oldValue);
  })
</script>

<style scoped>
  .person {
    background-color: skyblue;
    box-shadow: 0 0 10px;
    border-radius: 10px;
    padding: 20px;
  }
  button {
    margin: 0 5px;
  }
  li {
    font-size: 20px;
  }
</style>